In this project we will be attempting to study cell surface antigens which are specific to tumors. For this purpose we have adapted a technique for the production of antibodies of restricted heterogeneity in vitro. The objectives here will be to define the antigenic relationships between different closely related murine lymphoid tumors, and to determine the degree of overlapping in the array of tumor specific antigens of these different tumors. In addition, we will be attempting to produce antibodies which recognize human tumor specific antigens, particularly in leukemia and lymphoma. These antibodies against human tumor antigens may find application in immunodiagnosis and immunotherapy.